1. Field
The present embodiments relates to a cathode for an organic light emitting device and an organic light emitting device using the cathode, and more particularly to a cathode for an organic light emitting device configured to prevent the reflection of external light and an organic light emitting device using the cathode.
2. Description of the Related Technology
An electroluminescent device, especially an organic light emitting device is a device using light generated when electrons and holes are combined and dissipate to emit light.
An electroluminescent device can include an electrode for injecting holes, an electrode for injecting electrons, and a light emitting layer, and has a lamination structure in which the light emitting layer is interposed between the electrode for injecting the holes and the electrode for injecting the electrons. Among the electroluminescent devices, a device including a light emitting layer formed of a monomer organic material or a polymer is especially called a “organic light emitting device”.
Recent technologies for replacing the circularly polarizing plate have poor emission efficiency.
Methods of using an optical interference filter, which prevents the reflection through a destructive interference of reflected lights by using a metal-dielectric multi-layered thin film has limitations on the optical interference filter having to function as an electrode of the organic light emitting device. Although the electrode of an organic light emitting device should have the work function of a proper range in order to smoothly inject a charge (hole, electron) to the light emitting layer, the optical interference filter cannot have the work function required for functioning as the electrode of the organic light emitting device. As a result, the injection of the hole or the electron is not smooth in the electrode of the organic light emitting device, which makes the emission efficiency of the organic light emitting device deteriorated.